Journal of Invasive Cardiology

Discussion. No reflow phenomenon is frequently observed during PCI in lesions with a large thrombus burden.2 This may be attributed mainly to distal embolization of thrombus in such lesions, although there are other possible mechanisms for this phenomenon, such as microvascular damage and spasm.10,11 Patients with distal embolization and no reflow have significantly higher rates of myocardial infarction and death (approaching 20%) compared to patients without these complications.12,13 In a series of patients who were treated with transluminal extraction catheter atherectomy (Interventional Technologies, Bellevue, Washington), 18.5% of patients with distal embolization died in the hospital.14
Vasodilators have been the primary pharmacological treatment of no reflow.15–17 Intracoronary verapamil, nitroprusside and adenosine have been shown to be effective in the treatment of no reflow. The mechanism of action may be improvement in microvascular circulation and may be unrelated to embolic phenomena. Thus, these agents may not be enough to prevent or relieve no reflow and distal embolization when treating a lesion with a large amount of embolization source, such as large bulky thrombus.
Previous studies18,19 demonstrated that thrombolytic agents and glycoprotein IIb/IIIa inhibitors dissolved coronary thrombus and improved TIMI flow grade. Furthermore, the efficacy of glycoprotein IIb/IIIa inhibitor as an adjunctive therapy for primary angioplasty was demonstrated.20,21 However, it may not be possible to dissolve all thrombus with thrombolytic agents or glycoprotein IIb/IIIa inhibitors in lesions with large thrombus burden. Thus, the risk of no reflow and distal embolization might remain when treating such lesions.20
Covered stents with suitable length and compatible covering have the potential to entrap thrombus, which would otherwise embolize during deployment.22 However, embolization may occur in a lesion with a large thrombus burden while delivering the stent to the lesion through thrombus.
The AngioJet Rapid Thrombectomy System (Possis Medical, Minneapolis, Minnesota) uses the Bernoulli effect to aspirate friable pathology such as poorly organized thrombus.23 This device has demonstrable success in extracting thrombus from both diseased vein grafts and native coronary arteries. However, in a pilot study of the AngioJet,24 no reflow was observed in 13% of the lesions while attempting thrombectomy.
Recently, devices to trap embolic material have been introduced.3–8 These devices fall into two general types. One is the filter-type device that traps debris during intervention and is then collapsed and withdrawn from the artery with the trapped debris.8 However, in lesions with large thrombus burden, no reflow and distal embolization may occur while delivering the filter-type device through thrombus.
The other embolization containment device consists of a distal balloon, which occludes the artery during intervention, and a small catheter for aspiration of debris.3–8 Stein et al.25 demonstrated the concept of balloon occlusion and transluminal aspiration to prevent distal embolization. A balloon catheter was inflated at the segment distal to the lesion in a saphenous vein graft to prevent distal embolization while PCI was performed with another balloon catheter. The particulate debris was aspirated with a Dorros Infusion/Probing Catheter (USCI, Billerica, Massachusetts). The balloon catheter at the distal segment was then deflated. However, this technique does not allow the deployment of stents.
The PercuSurge containment system is an advanced system that uses this concept.3–8 The PercuSurge GuardWire Plus is constructed of 0.014´´ nitinol hypotube with a 35 mm radio-opaque, shapeable, steerable tip. Incorporated in the distal wire is a 5.5-mm long elastomeric balloon with a 0.041–0.043´´ crossing profile and available inflated diameters of 3.0–6.0 mm.4 Thus, the low profile of the PercuSurge GuardWire Plus minimizes the risk of distal embolization and no reflow while delivering it through thrombus, although meticulous guidewire manipulation is essential. A detachable inflation adapter accesses the hypotube lumen by displacing a small seal, allowing inflation of the balloon. This system allows stenting while the distal occlusion balloon is inflated. After PCI, an aspiration catheter (Export catheter) with an internal lumen diameter of 0.040´´ is advanced over the PercuSurge GuardWire Plus and allows removal of particulate debris using a 20 ml locking syringe before deflation of the occlusion balloon. Following manual aspiration, the aspiration catheter is removed and the distal occlusive balloon is deflated.4
The efficacy of the PercuSurge containment system for the treatment of diseased saphenous vein grafts has been demonstrated with encouraging results of a decreased incidence of distal embolization.3,4 Carlino et al.3 performed stenting with the PercuSurge GuardWire in 15 degenerated saphenous vein grafts. There were no distal embolizations or major in-hospital complications, including Q-wave and non-Q wave myocardial infarctions. In 10 of 15 patients, macro- or microscopic debris was observed. Webb et al.4 demonstrated no procedural complications except for 3 post-procedure non-Q wave myocardial infarctions (11.1%) in 27 saphenous vein grafts. Particulate material was identified after 21 of 23 procedures suitable for analysis. Recently, the randomized Saphenous vein graft Angioplasty Free of Emboli Randomized (SAFER) trial9 demonstrated a lower in-hospital major adverse cardiac event rate (8.8% versus 17.3%; p < 0.001), which was mainly due to a lower procedural myocardial infarction rate (8.4% versus 16.5%; p < 0.001) after PCI with the PercuSurge GuardWire Plus system in saphenous vein grafts compared to PCI without distal protection devices.
In another study,5 the PercuSurge GuardWire system was used when PCI in a native coronary artery was performed in 8 patients with acute myocardial infarction. Thrombus was aspirated in 7 of the 8 patients; in 1 patient, the system could not negotiate the angulated take-off of the LCX. Final TIMI grade 3 flow was observed in 5 of the 7 patients (71%). Because there are other possible mechanisms of slow or no reflow phenomenon, such as microvascular damage and spasm, it may be difficult to evaluate the efficacy of this device in patients with acute myocardial infarction without a randomized trial. To evaluate the efficacy of the PercuSurge GuardWire Plus system in acute myocardial infarction patients, the randomized Enhanced Myocardial Efficacy and Removal by Aspiration of Liberalized Debris (EMERALD) trial is now ongoing.
A case report by De Biase et al. showed successful treatment of a lesion with large thrombus burden using the PercuSurge GuardWire system.6 In this case, a glycoprotein IIb/IIIa inhibitor was used as adjunctive therapy. This drug may be useful as an adjunct to PCI with the embolization containment device in thrombotic lesions. In the present case, because decrease in hemoglobin had been observed before intervention, a glycoprotein IIb/IIIa inhibitor was not used. Thus, prevention of distal embolism and no reflow might be solely due to the embolization containment device, because thrombus-like material was retrieved through the aspiration catheter, which would have otherwise caused distal embolism and no reflow. However, if there is no contraindication, it may be recommended to use glycoprotein IIb/IIIa inhibitor as an adjunctive therapy.20,21
Angiography cannot be performed while inflating the distal occlusion balloon in a lesion of a saphenous vein graft, making assessment of the lesion and stent placement more difficult. However, contrast may be injected to confirm the appropriate position of the balloon catheter or stent when treating a lesion in a native coronary artery, because there is coronary flow into side branches (Figure 2). However, it means that this system does not prevent distal embolization into the branches proximal to the distal occlusion balloon. Thus, when there is a sidebranch, it is important to position the distal occlusion balloon at the segment proximal to the branch.
This device has some limitations. First, the distal occlusion balloon causes ischemia that may not be tolerated by some patients,3 although the present case did not have chest pain or electrocardiographic change during long inflation of the occlusion balloon, probably because of collateral circulation. Second, the distal occlusion balloon may cause vessel injury,7 although it is inflated at low pressure. Third, the aspiration catheter might not remove all particles trapped in the artery.
The PercuSurge GuardWire Plus temporary occlusion and aspiration system may be useful in lesions with large thrombus burden. Further large-scale studies, such as the EMERALD trial, are required to confirm the usefulness of this system.